1. Field of the Invention
The invention relates to an electric-powered bicycle, more particularly to an electric-powered bicycle that is operable in an automatic driving mode and a boosting driving mode.
2. Description of the Related Art
Electric-powered bicycles have been developed to permit forward movement of the bicycle without the need for applying a large amount of force during heavy load conditions. In use, when the bicycle is moving along an uphill slope, or when the rider is tired and wishes to stop pedaling the bicycle, the power source of an electric driving motor of the bicycle is activated for automatic or boosting bicycle driving movement so as to conserve the energy of the rider. The speed of the bicycle is then controlled by operating a twist grip throttle of a speed control unit of the bicycle. When the power source of the electric driving motor is deactivated, the bicycle can be moved forward in a manual driving mode only by pedaling the same. At this time, even if the twist grip throttle of the speed control unit is moved to an operative position, the electric driving motor will not generate a driving power output.
A main drawback of the conventional electric-powered bicycle resides in its insufficient safety features. Unlike a motorcycle which employs a gas engine that generates sounds or vibrations to alert the rider of the running status of the gas engine, the rider of the conventional electric-powered bicycle is unable to detect if the power source of the electric driving motor is activated unless he or she observes the state of the power switch. Thus, accidental operation of the twist grip throttle while the electric-powered bicycle is parked, such as when the rider is talking to a passer-by, with the power source of the electric driving motor in an activate state will result in forward surging movement of the bicycle, thereby resulting in danger.